삼산화텅스텐

SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.

VENTILATION CONTROL: ONE OF THE MOST IMPORTANT ENGINEERING CONTROL MEASURES IS VENTILATION- EITHER GENERAL OR LOCAL EXHAUST. /TUNGSTEN/

SRP: Local exhaust ventilation should be applied wherever there is an incidence of point source emissions or dispersion of regulated contaminants in the work area. Ventilation control of the contaminant as close to its point of generation is both the most economical and safest method to minimize personnel exposure to airborne contaminants.

3.0 [mg/m3], as W, respirable particulate matter

8 hr Time Weighted Avg (TWA): 5 mg/cu m; 15 min Short Term Exposure Limit (STEL): 10 mg/cu m. /Tungsten metal and insoluble compounds, as W/

13 [mg/m3]

420 [mg/m3]

2500 [mg/m3]

ATMOSPHERIC FATE: Most tungsten compounds have low pressures at 25 °C and are expected to exist solely in the particulate phase in the ambient atmosphere. Particulate-phase tungsten compounds may be removed from the air by wet and dry deposition. (SRC)

In February 1976, the avg concn of particle-born tungsten in stack gases of two coal-burning units at a western state power plant ranged from 2.0 to 23.2 ug/cu m(1); the avg concn of tungsten born by particles in the power plant plume ranged from 0.0050 to 0.019 ug/cu m(1). Gases from three different municipal waste deposits in British Columbia, Canada were sampled and analyzed for volatile tungsten compounds, such as tungsten carbonyls (e.g., W(CO)4)(2). At these locations, volatile tungsten compounds were found in concns ranging from 0.005-0.01 ug of W per cu m(2).

ONLY VERY SMALL CONCN OF TUNGSTEN...IN ATMOSPHERE...RELATED TO INDUST EMISSIONS OR...NUCLEAR FALLOUT. LEVELS...USUALLY...LESS THAN 1.5 NG/CU M IN AIR. ...ISOTOPES...PRODUCED IN NUCLEAR EXPLOSIONS ON SOME OCCASIONS IN LARGE AMT. THESE...WIDELY DISTRIBUTED IN ENVIRONMENT PRIMARILY AS TUNGSTIC OXIDE.

The production and use of tungsten compounds as cutting tools, abrasion resistant surfaces, and forming tools (e.g., tungsten carbide); filaments (e.g., tungsten metal and alloys); catalysts (e.g., tungsten oxides, sulfides, and heteropoly complexes); thin films (e.g., tungsten disulfide); and dyes and pigments (e.g., organic tungsten)(1) may result in the release of tungsten to the environment through various waste streams(SRC). Tungsten may be released to soil as a contaminate in phosphate fertilizers and manure(2,3). Only small concns of tungsten have been released into the atmosphere primarily by industrial emissions and nuclear fall-out(4).

Tungsten compounds are expected to exist as ions or insoluble solids in the environment(1) and therefore volatilization from moist soil and water surfaces is not expected to be an important fate process(SRC). Tungsten compounds are not expected to volatilize from dry soil surfaces based upon their ionic character and low vapor pressures(SRC).

...WHITE RATS /GIVEN/ A SINGLE INTRATRACHEAL DOSE OF 50 MG...TUNGSTEN TRIOXIDE ...IN 0.5 ML SALINE & SACRIFICED...AFTER 4, 6 & 8 MO. HISTOLOGICAL CHANGES WERE LIMITED TO THE LUNGS & CONSISTED OF PROLIFERATIVE REACTION OF THE LYMPHOID AND HISTIOCYTIC ELEMENTS, PARTICULARLY AT THE SITE OF ACCUMULATION OF THE ADMIN DUST, WITH SUBSEQUENT MILD FIBROSIS. THE WALLS OF SMALL VESSELS WERE THICKENED & THEIR ENDOTHELIUM SWOLLEN.

IN A SERIES OF FEEDING EXPERIMENTS, YOUNG RATS WERE FED FOR PERIOD OF 70 DAYS WITH DIFFERENT CONCN OF...TUNGSTIC OXIDE...MIXED WITH PURINA DOG CHOW. ...TUNGSTIC OXIDE EQUIVALENT TO 3.96% W.../WAS/ MARKEDLY TOXIC, CAUSING INITIAL WEIGHT LOSS FOLLOWED BY THE DEATH OF ALL ANIMALS...WITHIN 10 DAYS. IN DIETS HAVING EQUIVALENT OF 0.5% W...TUNGSTIC OXIDE PRODUCED DEATH IN 3/4 OF THE RATS...

DIETS CONTAINING ABOUT 0.5% W IN THE FORM OF...TUNGSTIC OXIDE...DO NOT KILL...RABBITS, ALTHOUGH THEIR GROWTH RATE IS DECREASED. ... AT HIGHER LEVELS...TUNGSTIC OXIDE (3.96%)...IN DIET ARE LETHAL TO RABBITS...

DIETS CONTAINING ABOUT 0.5% TUNGSTEN IN FORM OF...TUNGSTIC OXIDE...DO NOT KILL RATS & RABBITS, ALTHOUGH THEIR GROWTH RATE IS DECR. ... AT HIGHER LEVELS...TUNGSTIC OXIDE (3.96% W)...IN THE DIET...LETHAL TO RABBITS & RATS.

Tungsten exists in several oxidation states, 0, 2+, 3+, 4+, 5+, and 6+(1,2). The most stable is 6+ with the lower states being relatively unstable(2). Tungsten exist as ions in combination with one or more elements, e.g., oxygen(1). Tungsten in natural waters is in the form of tungstate (i.e., WO4- 2) and other tungsten polyanions(3). There are no reports of tungsten organic complexes(3). Bivalent tungsten exists only as halogen compounds(1). Tungsten has a strong tendency to form complexes exemplified by a large series of heteropoly acids formed with oxides of phosphorus, arsenic, vanadium, and silicon, among others (e.g., phosphotungstic acid)(2). In addition, compounds of tungsten exist in which tungsten occurs in more than one valence state(2). Tungsten forms a series of oxyhalides (e.g., WOCl4, WO2Cl2, and WOBr4)(2).

In 1980, the concn of tungsten in municipal sewage sludges from 23 US cites ranged from 0.65-140 ppm dry wt(1). The mean concn of tungsten in sewage sludges from US cites was 19.4 mg/kg, dry wt (samples=16; range, 0.9-99.6 mg/kg, dry wt)(2). In Iowa, the mean concn of tungsten in sewage sludges was 4.3 mg/kg (samples=44; range, 0.5-62 mg/kg)(2). The concn of tungsten in incinerator ash from the Barcelona (Spain) Urban Waste Incinerator plant ranged from 5-21 ug/g(3).

The average tungsten concentration in the earth's crust is about 0.006%. Tungsten occurs naturally as tungstate, mainly in compounds such as wolframaites and scheelites. Tungsten exists in several oxidation states, 0, 2+, 3+, 4+, 5+, and 6+. The most stable is 6+ with the lower states being relatively unstable. Tungsten exist as ions in combination with one or more elements, e.g., oxygen. The production and use of tungsten compounds as catalysts (e.g., tungsten oxides and sulfides); cutting and forming tools (e.g., tungsten carbide); filaments (e.g., tungsten metal and alloys); and dyes and pigments (e.g., organic tungsten) may result in the release of tungsten to the environment through various waste streams. Only small concentrations of tungsten have been released into the atmosphere primarily by industrial emissions and nuclear fall-out. If released to air, most tungsten compounds have low vapor pressures and will exist solely in the particulate phase in the ambient atmosphere. Particulate-phase tungsten compounds may be removed from the air by wet and dry deposition. If released to soil, tungsten compounds will have moderate to low mobility based upon a sorption coefficients ranging from 10 to 50,000 at pHs 5 to 6.5. Tungsten compounds are will exist as ions or insoluble solids in the environment and therefore volatilization from moist soil surfaces will not be an important fate process. Tungsten compounds will not volatilize from dry soil surfaces based upon their ionic character and low vapor pressures. If released into water, tungsten compounds will adsorb to suspended solids and sediment based upon their range or sorption coefficients. Tungsten in natural waters is in the form of tungstate (i.e., WO4- 2) and other tungsten polyanions. Tungsten compounds will exist as ions or insoluble solids in the environment and therefore volatilization from water surfaces will not be an important fate process. Occupational exposure to tungsten compounds may occur through inhalation of dust and dermal contact with this compound at workplaces where tungsten compounds are produced or used. (SRC)

Basic treatment: Establish a patent airway. Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if needed. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . Anticipate seizures and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with normal saline during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 ml/kg up to 200 ml of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool ... . Cover skin burns with dry sterile dressings after decontamination ... . /Poison A and B/

Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in respiratory arrest. Positive pressure ventilation techniques with a bag valve mask device may be beneficial. Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start an IV with D5W /SRP: "To keep open", minimal flow rate/. Use lactated Ringer's if signs of hypovolemia are present. Watch for signs of fluid overload. Consider drug therapy for pulmonary edema ... . For hypotension with signs of hypovolemia, administer fluid cautiously. Watch for signs of fluid overload ... . Treat seizures with diazepam (Valium) ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Poison A and B/

Used to make tungstates (used for x-ray screens and fireproofing fabrics), alloys, and yellow pigment in ceramics; [HSDB] Used as a catalyst for synthesis of organometallic compounds; [Ullmann]

Metal Preparation and Pouring [Category: Foundry]

Ceramics making [Category: Hobbies]

Mfr of tungstates which are used for x-ray screens and for fireproofing fabrics.

To form metal by reduction; alloys; yellow pigment in ceramics

Prepn from sodium tungstate: Hein, Herzog, in Handbook of Preparative Inorganic Chemistry vol 2, G Brauer, ed (Academic Press, New York, 2nd ed, 1965) pp. 1423-1424.

Scheelite ore is treated with hydrochloric acid and the resulting product dissolved out with ammonia. The complex ammonium tungstate can then be ignited to tungstic oxide.

Tungsten ore concentrates + sodium carbonate (ore roasting/water leaching/calcination); ammonium paratungstate (calcination)

Petrochemical Manufacturing

Tungsten oxide (WO3): ACTIVE

TUNGSTEN TRIOXIDE-TITANIUM DIOXIDE CATALYST USED FOR THE REDUCTION OF NITROGEN OXIDES IN FLUE GAS TREATMENT.

AS CATALYST. NITROGEN OXIDES PRESENT IN EXHAUSTS OR IN INDUSTRIAL WASTE GASES ARE REDUCED BY PASSAGE OVER A CATALYST MASS CONTAINING IRON & TUNGSTEN OXIDES IN THE ATOMIC RATIO IRON:TUNGSTEN OF 1.0:0.005-0.8.

X-RAY CONTRAST MEDIA COMPRISE 10-50% TANTALUM, HAFNIUM, TUNGSTEN, ONE OF THEIR PURE OXIDES OR INSOL SALTS, OR A PARTIALLY PURIFIED ORE CONTAINING GREATER THAN OR EQUAL TO 1 OF THESE SUBSTANCES, & A VISCOUS LIQ CARRIER. THESE COMPOSITIONS CAN BE PREPD EASILY WITHOUT SPECIALIZED APPARATUS, SHOW A HIGH AFFINITY FOR X-RAY, & CAN BE USED WITH CONVENTIONAL X-RAY APPARATUS.